Control device

1. A control device for causing a print performing unit to perform a print, the print performing unit including a print head on which a plurality of image forming elements is formed, the control device comprising: one or more processors; and a memory that stores a computer program including instructions executed by the one or more processors, wherein the instructions cause the one or more processors, when executed by the one or more processors, to function as: a first generating unit configured to generate a first type of processed image data by executing a first type of image process on target image data of a process target in accordance with an error diffusion method using a first error diffusion matrix; and a supplying unit configured to supply the first type of processed image data to the print performing unit in a case where the first type of processed image data is generated, wherein the first generating unit includes a compensating unit configured to execute a compensation process on a target pixel within the target image data for compensating variability of outputs of the plurality of the image forming elements, by using correcting data for a target image forming element which is to form an image at a position corresponding to the target pixel on the print medium, the correcting data is data acquired by using a value equivalent to a value calculated by multiplying a first coefficient by a first difference which is a difference between a target value and a first value, the target value is acquired by using characteristic data corresponding to the target image forming element, the first value is acquired by using characteristic data corresponding to a first image forming element within the plurality of image forming elements, the first image forming element is an image forming element which is to form a first neighbor raster neighboring a target raster formed on the print medium by the target image forming element, the first image forming element is an image forming element which is to form an image at a position corresponding to a first pixel on print medium, the first pixel being a pixel for which an error value is calculated before the target pixel, the characteristic data is data related to an output of an image forming element corresponding to the characteristic data, the first error diffusion matrix indicates M1 (M1 equal to or more than 2) pieces of error diffusion coefficients corresponding to M1 pieces of peripheral pixels positioned at the periphery of the target pixel, the first coefficient is decided based on a ratio between a summation of the M1 pieces of error diffusion coefficients and a summation of M2 (M2 less than M1) pieces of error diffusion coefficients corresponding to M2 pieces of peripheral pixels within the M1 pieces of peripheral pixels, and the M2 pieces of peripheral pixels are included in one or more rows other than a row including the target pixel.

2. The control device as in claim 1 , wherein the first neighbor raster is a raster adjacent to the target raster.

3. The control device as in claim 1 , wherein in a case where a first mode is selected by a user, the first generating unit is configured to generate the first type of processed image data in accordance with the error diffusion method using the first error diffusion matrix, in a case where a second mode is selected by the user, the first generating unit is configured to generate the first type of processed image data in accordance with the error diffusion method using a second error diffusion matrix, the second error diffusion matrix indicates N1 (N1 more than M1) pieces of error diffusion coefficients corresponding to N1 pieces of peripheral pixels positioned at the periphery of the target pixel, in the first mode, the first coefficient is decided based on the ratio between the summation of the M1 pieces of error diffusion coefficients and the summation of the M2 pieces of error diffusion coefficients corresponding to the M2 pieces of peripheral pixels within the M1 pieces of peripheral pixels, in the second mode, the first coefficient is decided based on a ratio between a summation of the N1 pieces of error diffusion coefficients and a summation of N2 (N2 less than N1) pieces of error diffusion coefficients corresponding to N2 pieces of peripheral pixels within the N1 pieces of peripheral pixels, and the N2 pieces of peripheral pixels are included in one or more lines other than a line including the target pixel.

4. The control device as in claim 1 , wherein the target value is an average value of L+1 (L equal to or more than 1) pieces of characteristic data including one piece of characteristic data corresponding to the target image forming element and L pieces of characteristic data corresponding to L pieces of image forming elements which are to form L pieces of rasters neighboring the target raster within the plurality of image forming elements, and the first value is an average value of L+1 pieces of characteristic data including one piece of characteristic data corresponding to the first image forming element and L pieces of characteristic data corresponding to L pieces of image forming elements which are to form L pieces of rasters neighboring the first neighbor raster within the plurality of image forming elements.

5. The control device as in claim 1 , wherein in a case where a third mode is selected by a user, the first generating unit is configured to generate the first type of processed image data by executing the first image process on the target image data in accordance with the error diffusion method, and the instructions cause the one or more processors, when executed by the one or more processors, to further function as: a second generating unit configured to generate a second type of processed image data by executing a second image process in accordance with a dither method on the target image data in a case where a fourth mode is selected by the user, the supplying unit is further configured to supply the second type of processed image data to the print performing unit in a case where the second type of processed image data is generated, and the second generating unit is configured to generate the second type of processed image data by executing the second type of image process without executing the compensation process.

6. The control device as in claim 1 , wherein the first generating unit includes: a halftone process unit configured to generate the first type of processed image data by executing a halftone process on the target image data in accordance with the error diffusion method, and the halftone process unit comprises: a correcting unit configured to generate a corrected value by correcting a value of the target pixel within the target image data by using a plurality of error values corresponding to a plurality of peripheral pixels positioned at a periphery of the target pixel; a deciding unit configured to decide, by comparing the corrected value and a threshold, whether or not an image is to be formed at the position corresponding to the target pixel on the print medium; and a compensating unit configured to execute the compensation process for calculating an error value corresponding to the target pixel by using the corrected value and the correcting data in a case where it is decided that the image with respect to the target pixel is to be formed.

7. The control device as in claim 1 , wherein the compensating unit is configured to execute the compensation process for generating compensated image data by generating a compensated pixel from the target pixel within the target image data, and the first generating unit further includes a halftone process unit configured to generate the first type of processed image data by executing a halftone process on the compensated image data in accordance with the error diffusion method.

8. The control device as in claim 1 , wherein the image forming element is a nozzle for discharging ink, the compensation process is a process for compensating variability of ink discharging volumes of the plurality of image forming elements, and the characteristic data is data related to the ink discharging volume of a corresponding image forming element.

9. A non-transitory computer-readable storage medium storing a computer program for a control device, the computer program including instructions for ordering one or more processes of the control device to execute: generating a first type of processed image data by executing a first type of image process on target image data of a process target in accordance with an error diffusion method using a first error diffusion matrix; and supplying the first type of processed image data to the print performing unit in a case where the first type of processed image data is generated, wherein the generating the first type of processed image data includes executing a compensation process on a target pixel within the target image data for compensating variability of outputs of the plurality of the image forming elements using correcting data for a target image forming element forming an image at a position corresponding to the target pixel on the print medium, the correcting data is data acquired by using a value equivalent to a value calculated by multiplying a first coefficient by a first difference which is a difference between a target value acquired by using characteristic data corresponding to the target image forming element and a first value acquired by using characteristic data corresponding to a first image forming element within the plurality of image forming elements, the first image forming element is an image forming element forming a first neighbor raster neighboring a target raster formed on the print medium by the target image forming element, the first image forming element is an image forming element forming an image at a position corresponding to a first pixel on print medium, the first pixel being a pixel for which an error value is calculated before the target pixel, the characteristic data is data related to an output of an image forming element corresponding to the characteristic data, the first error diffusion matrix indicates M1 (M1 equal to or more than 2) pieces of error diffusion coefficients corresponding to M1 pieces of peripheral pixels positioned at the periphery of the target pixel, the first coefficient is decided based on a ratio between a summation of the M1 pieces of error diffusion coefficients and a summation of M2 (M2 less than M1) pieces of error diffusion coefficients corresponding to M2 pieces of peripheral pixels within the M1 pieces of peripheral pixels, and the M2 pieces of peripheral pixels are included in one or more rows other than a row including the target pixel.

10. A control device for causing a print performing unit to perform a print, the print performing unit including a print head on which a plurality of image forming elements is formed, the control device comprising: one or more processors; and a memory that stores a computer program including instructions executed by the one or more processors, wherein the instructions cause the one or more processors, when executed by the one or more processors, to function as: a first generating unit configured to generate a first type of processed image data by executing a first type of image process on target image data of a process target in accordance with an error diffusion method; and a supplying unit configured to supply the first type of processed image data to the print performing unit in a case where the first type of processed image data is generated, wherein the first generating unit includes a compensating unit configured to execute a compensation process on a target pixel within the target image data for compensating variability of outputs of the plurality of the image forming elements, by using correcting data for a target image forming element which is to form an image at a position corresponding to the target pixel on the print medium, the correcting data is data acquired by using a first difference which is a difference between a target value and a first value, and a second difference which is a difference between the first value and a second value, the target value is acquired by using characteristic data corresponding to the target image forming element, the first value is acquired by using characteristic data corresponding to a first image forming element within the plurality of image forming elements, the first image forming element is an image forming element which is to form a first neighbor raster neighboring a target raster formed on the print medium by the target image forming element, the first image forming element is an image forming element which is to form an image at a position corresponding to a first pixel on print medium, the first pixel being a pixel for which an error value is calculated before the target pixel, the characteristic data is data related to an output of an image forming element corresponding to the characteristic data, the second value is acquired by using characteristic data corresponding to a second image forming element within the plurality of image forming elements, the second image forming element is an image forming element which is to form a second neighbor raster neighboring the first neighbor raster, and the second image forming element is an image forming element which is to form an image at a position corresponding to a second pixel on print medium, the second pixel being a pixel for which an error value is calculated before the first pixel.

11. The control device as in claim 10 , wherein the second neighbor raster is a raster adjacent to the first neighbor raster.

12. The control device as in claim 10 , wherein the correcting data is data acquired by using a value equivalent to a value calculated by multiplying a first coefficient by the first difference, and a value equivalent to a value calculated by multiplying a second coefficient by the second difference, and the first coefficient is greater than the second coefficient.

13. The control device as in claim 12 , wherein the first generating unit is configured to generate the first type of processed image data in accordance with the error diffusion method using a first error diffusion matrix, the first error diffusion matrix indicates M1 (M1 equal to or more than 2) pieces of error diffusion coefficients corresponding to M1 pieces of peripheral pixels positioned at a periphery of the target pixel, the first coefficient is decided based on a ratio between a summation of the M1 pieces of error diffusion coefficients and a summation of M2 (M2 less than M1) pieces of error diffusion coefficients corresponding to M2 pieces of peripheral pixels within the M1 pieces of peripheral pixels, the M2 pieces of peripheral pixels is included in one or more lines other than a line including the target pixel, the second coefficient is decided based on a ratio between a summation of the M2 pieces of error diffusion coefficients and a summation of M3 (M3 less than M2) pieces of error diffusion coefficients corresponding to M3 pieces of peripheral pixels within the M2 pieces of peripheral pixels, and the M3 pieces of peripheral pixels are included in one or more rows other than a row including the first pixel.